Apparatuses for determining the ametropia of eyes are suitable for determining the refractive error of an eye of a patient. This determining is the basis for prescriptions of corrective lenses, such as spectacles or contact lenses, for correcting the refractive error of the eye. Data obtained by such an apparatus conventionally comprise an amount of a spherical refractive error and an amount and an orientation of an astigmatic refractive error.
Such conventional apparatuses also referred to as auto refractors may comprise a wave front sensor such, as a Hartmann-Shack-sensor. For measuring the ametropia, a small region on the retina of the eye to be inspected is illuminated by a measurement light, beam. The light of the measurement light, beam reflected at the retina is emitted from the eye and is directed onto an entrance window of the wave front sensor. Subsequently, the ametropia of the eye may be determined based on the measured wave front.
While providing a relatively high measurement accuracy, apparatuses for determining the ametropia of an eye comprising a wave front sensor are expensive devices.
Accordingly, it is an objective of the present invention to propose an apparatus for determining the ametropia of an eye which is realizable simpler and, thus, less expensive and, in particular, does not have a wave front sensor.